Wednesday, January 23, 2013

Modest But Impactful Snow

Friday's light snowfall may be a higher impact snow despite not being the biggest storm that's ever come down the pike. Timing is such, being that it will arrive on Friday afternoon in time for the PM Rush Hour, which makes these snows a bit more "fun" from a driving standpoint (quotes intend sarcasm, of course) and means a likely slower-than-usual commute home.

Modeling has come to some degree of consensus on this being not the biggest of storms but a 1-3 inch event, which is what most of the region is in line for, is still the biggest snowfall for most everyone south of Philadelphia or close to it.

Light snow should arrive Friday afternoon and continue through the evening hours before tapering off. There could be a couple of zones where snow may be a bit more generous than others -- south of the city is the most likely spot for these areas as the low that becomes the dominant feature tracks to our south and intensifies as it reaches the coast. There will be some energy that pushes across Pennsylvania, transferring to the low to the south, so precipitation may wane as snow pushes east from Pennsylvania to New Jersey. Both the Euro and GFS hint at this "wane" downstream of the Appalachians -- the Euro generally across the Lehigh Valley and Northern Jersey, the GFS around Philly and into suburban South Jersey.

Euro for 7 PM Friday showing the "brunt" of the light snow event in the region.

GFS modeled snowfall generally around 1-2" in the city, 2-3" west and south.

A few inches seems the most likely bet around the region -- Central/Southern Delaware into Cape May and along the coast to Atlantic City could pick up a three inch plus amount in spots but the rest of us look to be in line for one to three...I have the range at one to three as modeling may nudge slightly more moist down the line compared to where we're at now.

Most models are generally a tenth to a quarter inch on "precip" but given the cold air in place, ratios should help nudge some spots closer to three inches despite dry air negating the front end of the "storm". I don't think we'll see dramatic ramping up of moisture as we close in at this point unless the storm system can slow down and intensify a bit more quickly...it's not out of the realm of possibility but it's very much not likely to be a slower moving storm system. The jet and the main mid level flow in the country is rather rapid...the result of this is a faster moving storm system. In general, it's not the biggest snowfall you'll ever get -- modeling was a bit more robust earlier in the game but odds at this point favor this being a nice snowfall but not one we'll remember with a lot of note.